It is well known to employ resonators to tune the manifolds of internal combustion engines, especially engines that are used for powering automotive vehicles. Commonly assigned U.S. Pat. No. 5,162,621 discloses the use of a Helmholtz resonator to tune the manifold of an engine.
Typical intake manifold geometries provide an engine torque-speed characteristic that has a peak torque at a certain engine speed. Over a range of engine speeds beyond that certain engine speed, the torque dips. The present invention is directed toward reducing, or even eliminating, such a dip.
In one respect, the present invention relates to a new and improved Helmholtz resonator that can provide adaptive manifold tuning for the purpose of improving engine performance. More specifically, this aspect of the invention relates to endowing the neck of a Helmholtz resonator with means for selectively setting the effective transverse cross sectional area of communication that the neck provides between the Helmholtz resonator chamber and the air intake passage of the engine induction system. The selective setting is accomplished by an obturator, or valve, that is selectively positioned by an actuator to selectively restrict the neck opening. The actuator is under the control of one or more engine operating parameters, such as engine speed.
While the adaptive tuning is accomplished in an advantageous fashion by the organization and arrangement of air intake passage, plenum chamber, runners, and Helmholtz resonator, insofar as the applicants are aware, such organization and arrangement possesses novelty independently of the feature of selectively restricting the neck of the Helmholtz resonator, and such organization and arrangement constitutes a further aspect of the invention.
The foregoing, along with further features, advantages, and benefits of the invention, will be seen in the ensuing description and claims which are accompanied by drawings depicting a presently preferred embodiment of the invention according to the best mode contemplated at this time for carrying out the invention.